I just bought a pair of La Sportiva Solutions (43) in my regular shoe size (10-10.5). I wore them in the store for a bit and they felt fine, but I am quickly discovering that the left one absolutely kills my foot due to some issues with my big toe not wanting to curl at all. After a few minutes, I cannot even step on it, let alone climb.

Is there any way to stretch the left one a bit? The right one is OK, more or less.